This is a really interesting structure in the sense that it has served both as a mosque and a church over hundreds of years. And today, it has been turned into a museum and is a true reflection of the Byzantine architecture.

The Hagia Sophia just opposite the Blue Mosque became a museum in 1935. Since then you do not have to dress as in a normal mosque. To enter the oldest and largest cathedral in the world, you have to pay 25 TL or possess a Museum Pass.

Hagia Sophia Museum (Ayasofya Muzesi in Turkish), also known as the Church of the Holy Wisdom, was a cathedral built in Constantinople during the 6thcentury AD under the direction of the Byzantine emperor Junstinian I. It was completed in 537 AD after only 6 years construction and it is now a component of a UNESCO World Heritage Site called the Historic Areas of Istanbul. The current building stands on the foundations of a pagan temple and ruins of the original church said to have been built in 325 and then rebuilt after fire in 404. A second fire in 532 provided Justinian I an opportunity to rebuild this splendid structure with its 32 meter dome and two smaller semi-domes. Marble piers and newly renovated outside walls support the massive dome, which has partially collapsed a number of times. Sadly, you can see sections of gold mosaics and tiles missing from this magnificent and colourful building from when it was looted by the Venetians and the Crusaders in the 13th century. In 1453 it was repurposed as a mosque before being converted into the museum you see today in 1935.
(Hagia Sophia is closed on Monday. The winter visiting hours are from 09.00 to 17.00. Summer visiting hours are between 09.00 and 19.00. The final entry is one hour before closing. Passes are available at the box office in the museum. Entry fee is 25 TL.)

Hagia Sophia is a former Greek Orthodox patriarchal basilica.It was later turned into an imperial mosque, and now it is a museum in Istanbul, Turkey. It has a long history and has been used for different purposes through the passage of time.

Istanbul stands in the center of the two continents and in the center of Istanbul stands the grand Hagia Sophia. Hagia Sophias has been described as the ‘architectural wonder’ – the gem of the Byzantine empire, later the proud possession of the Ottomans and now the symbol of secular Turkey. The building has stood at the heart of the empire that laid claim on it. Such was the allure of Hagia Sophia that when Mehmet, the conqueror entered victorious into the city of Constantinople his first stop was the church of Hagia Sophia. A muslim priest was called in to read to Shahada and the Eastern Orthodox Cathedral that stood for 1000 years was now a mosque. There onwards, the grand structure of Sophia Hagia inspired the many other mosques built in Istanbul during the Ottoman rein, all looking like the prodigies of Hagia Sophia.
When Kemal Ataturk secularized Turkey, he converted Aya Sophia into a museum opening its doors to all sending out the message that Hagia Sophia was indeed a heritage of the world.

Santa Sofia was for nearly a thousand years, the largest enclosed space in the world and is still seen as one of the world's most important monuments. It is one of Turkey's most popular attractions, people are drawn by the sheer spectacle of its size, the architecture, mosaics and art. It was built in the sixth century by the Byzantine emperor Justinian. It is closed on Monday.

The Topkapi Palace was the primary residency of the sultans. It is a complex with heaps of buildings a huge garden area overlooking the Bosporus. I was impressed when I entered the first room and couldn’t believe that the rooms were getting more impressive the more you see. There are classy decorated domes and mosaics, simply splendid!
The entrance fee is 25 TL for the palace complex. If you want to visit the Harem as well which is the area were the sultan’s family and their servants lived undisturbed, you have to pay another 15 TL. Both is included in the Museum Pass.

The Topkapi Palace was the primary residency of the sultans. It is a complex with heaps of buildings a huge garden area overlooking the Bosporus. I was impressed when I entered the first room and couldn’t believe that the rooms were getting more impressive the more you see. There are classy decorated domes and mosaics, simply splendid!
The entrance fee is 25 TL for the palace complex. If you want to visit the Harem as well which is the area were the sultan’s family and their servants lived undisturbed, you have to pay another 15 TL. Both is included in the Museum Pass.

The Topkapi Palace (Topkapı Sarayı) is the imperial enclave of the Ottoman emperors for four centuries. It is lavishly decorated and houses some of the Prophet Mohammed’s belongings.
(Opening times are Monday, Wednesday to Sunday between 09:00 and 17:00. Entry is 25 TL. Harem is 15 TL)

It is a large palace in Istanbul, that was the primary residence of the Ottoman Sultans for almost 4 centuries . It contains important holy relics of the Muslim world. It is also a UNESCO world heritage site. Need to say anything more ?

Only the palace is the part of the tour which has so much to see and to be said. A guided tour is a must to really understand the meaning of the most popular attractions of Istanbul. In short, the Topkapi Palace was the imperial residence of the Ottoman Sultans, from Fatih Sultan Mehmet, the Conqueror, until 1856. It became a museum in 1924. Parts of the palace and the Harem, Baghdad Pavilion in Hall Revan, Sofa Pavilion, and the courtroom are distinguished by its architectural heritage, while in other sections artifacts are displayed which reflect the palace life. The museum also has collections from the imperial treasury including Chinese porcelain, weapons, calligraphy etc. It is closed on Tuesday.

The Galata Tower is on the other side of the city. From up there you have a stunning view of the Bosperus, a lot of sights in Sultanahmed and of course the area around the Galata tower. The entrance fee amounts to 20 TL which is a bit much in my opinion and another negative fact is that there is not much space up there and you always have to squeeze by the other people.

It is a medieval stone tower in the Galata/Karaköy quarter of the city of Istanbul. It lies on the northern side of the Golden Horn's junction with the Bosphorus.
Address: Bereketzade Mh., Galata Kulesi, Beyoğlu, Turkey
Opened: 1348
Height: 67 m

Walking further across the Galata bridge you will see the Galata Tower. The tower was built as Christea Turris (Tower of Christ) in 1348 during an expansion of the Genoese colony in Constantinople. This is is a medieval stone tower in the Galata. Built as watchtower to help protect the city especially by spotting fires, this still remains as one of the dominating structures in the city. The cone-capped cylinder dominates the skyline and offers a panoramic vista of Istanbul. The view from the top is completely breathtaking from every angle. Seeing some of the more modern structures from the top makes one realize how diverse this old city of Istanbul is.

The grand bazaar is open only till 7:30 so plan your day accordingly as this place offers many shops to buy souvenirs, lamps etc.
Just next to the grand bazaar is an old adda for hukkah. The place is full of people and is filled of hukkah smoke with different flavors. We sat there for few hours having apple flavour hukkah and tea. The hukkah is for 15 lira and each cay (chai) for 1 lira. The place had a beautiful shop for lamps, but as expected expensive. On the main metro/ tram road, there was a shop on left side where I bought my single lamp for 25 lira each for a small size. If you plan to buy lamps, you can set aside a budget of 30-50 Lira per lamp based on the size of the lamp.

This is one of the oldest and largest marketplaces in the world with more than 4000 shops selling everything from spices to carpets to antiques of any kind. For any tourist hoping to buy a few souvenirs, this is the place to be. This truly reminds you of the famous souks in various countries in the Middle East.

A trading center since 1461, the Grand Bazaar in Istanbul is one of the largest and oldest covered markets in the world, attracting between 250,000 and 400,000 shoppers daily. There are 61 covered streets and over 3,000 shops providing one of the most exciting shopping experiences. Here you can buy anything from fashion, jewellery, Turkish ceramics, carpets, textiles and spices. The complex houses two mosques, four fountains, two hamams, and several cafés and restaurants. In the centre is the high domed hall of the Cevahir Bedesten. To get there, take a tram to Beyazit, Üniversite or Sirkeci. Alternatively, the Grand Bazaar is around 15 minutes’ walk from the Aya Sofya/Blue Mosque area
(Opening times are Monday to Saturday between 09:00 and 19:00. Closed Sundays and bank holidays)
Traveller Tip: When shopping at the Spice Market or Grand Bazaar, taste before you buy, buy from a reputable, high-turnover supplier and pay in Turkish Lira.

Also popularly known as the Blue Mosque. The Blue Mosque is situated in Sultanahmet. You can enter for free when you dress appropriately (see 8 Lessons learned in Istanbul). The mosque is closed during the prayers.

The Sultan Ahmed Mosque (Turkish: Sultan Ahmet Camii) is a historic mosque in Istanbul. The mosque is popularly known as the Blue Mosque for the blue tiles adorning the walls of its interior. It was built from 1609 to 1616, during the rule of Ahmed I. Its Külliye contains a tomb of the founder, a madrasah and a hospice. The Sultan Ahmed Mosque is still popularly used as a mosque. This mosque is beautiful, not only from outside but the interior too.
Everything look so peaceful and reconcile.
Do avoid visiting at prayer time or within a half hour after the azan is chanted from the Mosque minarets because mosque closes for 90 minutes at each prayer time.

And lest we forget, there is also the New Year Party Fireworks which people view from the famous Taksim Square around the Golden Horn and the beautiful cruise on the Bosphorus. As the cruise crosses the first and reaches the 2nd bridge, one would get a unique chance to spend the early moments of the New Year on the crossroads between Asia and Europe.

The tour starts around 9.00 in the morning in Taksim Square. This square is famed for its array of restaurants, shops, and hotels. If you love shopping, you'll enjoy Taksim Square. Not just this, the Square also houses the Monument of the Republic inaugurated in 1928. You can also see the nostalgic tram that runs from the square along the avenue.

About Istanbul

Istanbul – One of the largest cities in Turkey and is quite fast paced like any of the metros around the world. It’s known for the mosques, palaces, Bosporus River, the Grand Bazaar & the Spice MarketRead More

Day 3: Post breakfast we checked out of Sophia Studio Apartment and left luggage in the luggage room. We then visited Grand Bazaar and walked to the Spice Market and explored the market between the two. Post that we had lunch and then chilled at Eminonu. In the evenings, we headed back to the apartment to collect our luggage. We took the overnight bus by Metro Turizm to Selcuk which departed at 09:30 pm from Istanbul.

Day 1: Took an early morning Qatar Airways flight at 04:10 am from Mumbai which arrived in Istanbul at 12:30 pm and checked into Sophia Studio Apartments in Sultanahmet. We visited Grand Bazaar to exchange currency (you get the best exchange rates there) and then headed to Galata Tower for the Sunset.

Day 2: After breakfast, we headed out to visit Blue Mosque, Hagia Sophia and Basilica Cistern. Post lunch we relaxed in the gardens outside Topkapi Palace and then headed to Istiklal Street to spend the evening.

As you stroll down the cobbled streets of Istanbul, history greets you at every step and culture is a constant companion. The palaces, mosques and churches of the city are artistic goldmines in their own right and the bazaars exude this infectious energy. The mezes are unending, the kebaps are always tender and the coffee is the most addictive of the lot. Entrenched in its prosperous heritage, Istanbul defines vibrance in a way no other place does.

Istanbul is one of the largest cities in Europe. Turkey's most populous city and its cultural and financial hub. Located on both sides of the Bosphorus, the narrow strait between the Black Sea and the Marmara Sea, Istanbul bridges Asia and Europe both physically and culturally. It is the only city which is spread over two continents!
Things to know about this city:
1. Atatürk Airport: Most international flights arrive at the Ataturk airport (other airport being Sabiha) and one can reach the main city by Havatas Muncipal service bus (11 TL) or by a private taxi (50 TL)
2. Two main neighborhoods to stay at:
i) Taksim square- Major tourist and leisure district known for its nightlife, restaurants and pubs.
ii) Sultanahmet- Old city, where all tourist attractions like the Blue Mosque, Hagia Sophia, Topkapi palace can be explored by foot.
3. Ortakoy neighborhood: Ortakoy is a vibrant neighborhood to explore. It has many cafeterias and tea houses around a square near the water or in the alleys, restaurants, bars, small shops and a market which gets very lively during the weekends. World class night clubs like Reina and Anjelique are also in this area, on the Bosphorus which one should not miss.
4. Kumpir: One cant miss eating Kumpir at Ortakoy! You would be remised not to try one of the town's signature dishes,a loaded baked potato pureed to perfection and stuffed to infinity with as many or as little toppings as your heart desires.
5. Galata Tower: City's tallest tower with a restaurant and cafe on the upper floor. Tickets to go can be booked online or instead one can visit Galata Roof Top Cafe which has the same view!
6. The following are the most famous attractions in Istanbul which shouldn't be missed. Also the days when these attractions are closed should be kept in mind before you plan your itinerary:
i) Blue Mosque or Sultan Ahmed mosque- no entry fee and closed during praying hours
ii) Hagia Sophia- 20 TL entry fee and closed on Mondays
iii) Topkapi Palace- Closed on Tuesdays
iv) Basilica Cistern- 20 TL entry fee
v) Hippodrome Square
vi) Dolmabahce Palace
7. Gulhane Park: Located adjacent to the Topkapi Palace, this urban park is a perfect place to have a peaceful lunch.
8. Princess Island one day excursion: The main feature of any of the Princes’ Islands is the sound of silence. All motorized vehicles are banned, making the islands an oasis of peace and quiet. Horse-drawn carriages and bicycles are the main transportation means on the islands.
But that’s not the only feature that makes the Princes’ Islands unique. You’ll find yourself walking or riding through narrow streets flanked by either untouched pine-forests or fine, wooden Victorian cottages.
Ferry will be available from Kabataş every morning which will take you to 4 of these islands. Early reservation for stay is mandatory in these islands since it gets full pretty fast.
9. Hookah/Sheesha: One can't leave Turkey without trying a Sheesha which is basically smoking flavored tobacco. Best place to pull sheesha would definitely be near Galata tower or Tophane area.
10. Grand Bazaar: The Grand Bazaar is one of the largest and oldest covered markets in the world, with 61 covered streets and over 3,000 shops which attract between 250,000 and 400,000 visitors daily. In 2014, it is listed No.1 among world's most-visited tourist attractions with 91,250,000 annual visitors.
11. Spice Market: Again a covered market, one of the largest spice bazaars in the world, also known as the Egyptian bazaar since all its goods are brought from Egypt. Goods such as Iranian saffron, Indian curry, Chinese flower tea, Turkish delight, Russian caviar etc are found in abundance.
12. Istiklal Street: Arguably the busiest pedestrian street in the world popular for shopping and snacking street, is lined with boutiques, cafes, consulates, restaurants, galleries, cinemas and banks, with residential apartments above. The avenue begins at Taksim square, the hub of this city.
13. Whirling Dervishes: Well known dance form, when the whirling dervish take the floor with the heavenly sounds of Sufi music, you can’t help but be transfixed. The right hand stretches to the infinite cosmos and the left towards the ever-grounding earth. Not a performance, but a form of worship.
14. Hammams: No trip to Turkey is complete without a visit to the famous baths, called hammams. Experiencing a few hours at these bathhouses, many of which date back hundreds of years, is a relaxing, rejuvenating and rich cultural experience.
15. Simit: A simit is a sesame seed-crusted bread with fluffier interior that found across the cuisines of the former Ottoman Empire, and the Middle East. Simits are often sold by street vendors, who either have a simit trolley or carry the simit in a tray on their head.

As such one needs 5 days to spend in Istanbul, there are many places, different food to try out.But was able to explore the sultanhemt place and underground city near it was really amazing. i was staying a hostel near the sultanhemet place .